Energies and damping rates of elementary excitations in spin-1 Bose-Einstein condensed gases

TL;DR

This paper employs a finite temperature Green's function approach within a self-consistent Hartree-Fock framework to analyze the energies and damping rates of elementary excitations in spin-1 Bose-Einstein condensates, ensuring Goldstone theorem compliance.

Contribution

It introduces a self-consistent dynamical Hartree-Fock model that accurately captures excitation properties and hybridization effects in spin-1 Bose gases at finite temperatures.

Findings

Calculated energies and damping rates for ^{23}Na and ^{87}Rb gases.

Model satisfies Goldstone theorem and correctly describes hybridization.

Provides insights into density and spin channel excitations.

Abstract

Finite temperature Green's function technique is used to calculate the energies and damping rates of elementary excitations of the homogeneous, dilute, spin-1 Bose gases below the Bose-Einstein condensation temperature both in the density and spin channels. For this purpose the self-consistent dynamical Hartree-Fock model is formulated, which takes into account the direct and exchange processes on equal footing by summing up certain classes of Feynman diagrams. The model is shown to fulfil the Goldstone theorem and to exhibit the hybridization of one-particle and collective excitations correctly. The results are applied to the gases of ^{23}Na and ^{87}Rb atoms.